/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.naming.resources;

import org.apache.naming.JndiPermission;
import org.apache.tomcat.util.buf.UDecoder;
import org.apache.tomcat.util.buf.UEncoder;
import org.apache.tomcat.util.http.FastHttpDateFormat;

import javax.naming.NameClassPair;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import javax.naming.directory.Attribute;
import javax.naming.directory.Attributes;
import javax.naming.directory.DirContext;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import java.security.Permission;
import java.util.*;

/**
 * Connection to a JNDI directory context.
 * <p/>
 * Note: All the object attribute names are the WebDAV names, not the HTTP
 * names, so this class overrides some methods from URLConnection to do the
 * queries using the right names. Content handler is also not used; the
 * content is directly returned.
 *
 * @author <a href="mailto:remm@apache.org">Remy Maucherat</a>
 */
public class DirContextURLConnection extends URLConnection {

	private static final UDecoder URL_DECODER = new UDecoder();

	// ----------------------------------------------------------- Constructors
	/**
	 * Directory context.
	 */
	protected DirContext context;


	// ----------------------------------------------------- Instance Variables
	/**
	 * Associated resource.
	 */
	protected Resource resource;
	/**
	 * Associated DirContext.
	 */
	protected DirContext collection;
	/**
	 * Other unknown object.
	 */
	protected Object object;
	/**
	 * Attributes.
	 */
	protected Attributes attributes;
	/**
	 * Date.
	 */
	protected long date;
	/**
	 * Permission
	 */
	protected Permission permission;
	/**
	 * Cache the path as it there is some processing required - particularly if
	 * the context is a ProxyDirContext.
	 */
	private String path = null;

	public DirContextURLConnection(DirContext context, URL url) {
		super(url);
		if (context == null)
			throw new IllegalArgumentException
					("Directory context can't be null");
		if (org.apache.naming.Constants.IS_SECURITY_ENABLED) {
			this.permission = new JndiPermission(url.toString());
		}
		this.context = context;
	}


	// ------------------------------------------------------------- Properties

	/**
	 * Connect to the DirContext, and retrieve the bound object, as well as
	 * its attributes. If no object is bound with the name specified in the
	 * URL, then an IOException is thrown.
	 *
	 * @throws IOException Object not found
	 */
	@Override
	public void connect() throws IOException {

		if (!connected) {

			try {
				date = System.currentTimeMillis();
				path = URL_DECODER.convert(getURL().getFile(), false);
				if (context instanceof ProxyDirContext) {
					ProxyDirContext proxyDirContext =
							(ProxyDirContext) context;
					String hostName = proxyDirContext.getHostName();
					String contextPath = proxyDirContext.getContextPath();
					if (hostName != null) {
						if (!path.startsWith("/" + hostName + "/"))
							return;
						path = path.substring(hostName.length() + 1);
					}
					if (contextPath != null) {
						if (!path.startsWith(contextPath + "/")) {
							return;
						}
						path = path.substring(contextPath.length());
					}
				}
				object = context.lookup(path);
				attributes = context.getAttributes(path);
				if (object instanceof Resource)
					resource = (Resource) object;
				if (object instanceof DirContext)
					collection = (DirContext) object;
			} catch (NamingException e) {
				// Object not found
			}

			connected = true;
		}
	}

	/**
	 * Return the content length value.
	 */
	@Override
	public int getContentLength() {
		return getHeaderFieldInt(ResourceAttributes.CONTENT_LENGTH, -1);
	}

	/**
	 * Return the content type value.
	 */
	@Override
	public String getContentType() {
		return getHeaderField(ResourceAttributes.CONTENT_TYPE);
	}

	/**
	 * Return the last modified date.
	 */
	@Override
	public long getDate() {
		return date;
	}

	/**
	 * Return the last modified date.
	 */
	@Override
	public long getLastModified() {

		if (!connected) {
			// Try to connect (silently)
			try {
				connect();
			} catch (IOException e) {
				// Ignore
			}
		}

		if (attributes == null)
			return 0;

		Attribute lastModified =
				attributes.get(ResourceAttributes.LAST_MODIFIED);
		if (lastModified != null) {
			try {
				Date lmDate = (Date) lastModified.get();
				return lmDate.getTime();
			} catch (Exception e) {
				// Ignore
			}
		}

		return 0;
	}

	protected String getHeaderValueAsString(Object headerValue) {
		if (headerValue == null) return null;
		if (headerValue instanceof Date) {
			// return date strings (ie Last-Modified) in HTTP format, rather
			// than Java format
			return FastHttpDateFormat.formatDate(
					((Date) headerValue).getTime(), null);
		}
		return headerValue.toString();
	}

	/**
	 * Returns an unmodifiable Map of the header fields.
	 */
	@Override
	public Map<String, List<String>> getHeaderFields() {

		if (!connected) {
			// Try to connect (silently)
			try {
				connect();
			} catch (IOException e) {
				//Ignore
			}
		}

		if (attributes == null)
			return (Collections.emptyMap());

		HashMap<String, List<String>> headerFields =
				new HashMap<String, List<String>>(attributes.size());
		NamingEnumeration<String> attributeEnum = attributes.getIDs();
		try {
			while (attributeEnum.hasMore()) {
				String attributeID = attributeEnum.next();
				Attribute attribute = attributes.get(attributeID);
				if (attribute == null) continue;
				ArrayList<String> attributeValueList =
						new ArrayList<String>(attribute.size());
				NamingEnumeration<?> attributeValues = attribute.getAll();
				while (attributeValues.hasMore()) {
					Object attrValue = attributeValues.next();
					attributeValueList.add(getHeaderValueAsString(attrValue));
				}
				attributeValueList.trimToSize(); // should be a no-op if attribute.size() didn't lie
				headerFields.put(attributeID, Collections.unmodifiableList(attributeValueList));
			}
		} catch (NamingException ne) {
			// Shouldn't happen
		}

		return Collections.unmodifiableMap(headerFields);

	}

	/**
	 * Returns the name of the specified header field.
	 */
	@Override
	public String getHeaderField(String name) {

		if (!connected) {
			// Try to connect (silently)
			try {
				connect();
			} catch (IOException e) {
				// Ignore
			}
		}

		if (attributes == null)
			return (null);

		NamingEnumeration<String> attributeEnum = attributes.getIDs();
		try {
			while (attributeEnum.hasMore()) {
				String attributeID = attributeEnum.next();
				if (attributeID.equalsIgnoreCase(name)) {
					Attribute attribute = attributes.get(attributeID);
					if (attribute == null) return null;
					Object attrValue = attribute.get(attribute.size() - 1);
					return getHeaderValueAsString(attrValue);
				}
			}
		} catch (NamingException ne) {
			// Shouldn't happen
		}

		return (null);

	}

	/**
	 * Get object content.
	 */
	@Override
	public Object getContent()
			throws IOException {

		if (!connected)
			connect();

		if (resource != null)
			return getInputStream();
		if (collection != null)
			return collection;
		if (object != null)
			return object;

		throw new FileNotFoundException(
				getURL() == null ? "null" : getURL().toString());

	}

	/**
	 * Get object content.
	 */
	@Override
	public Object getContent(@SuppressWarnings("rawtypes") Class[] classes)
			throws IOException {

		Object obj = getContent();

		for (int i = 0; i < classes.length; i++) {
			if (classes[i].isInstance(obj))
				return obj;
		}

		return null;

	}

	/**
	 * Get input stream.
	 */
	@Override
	public InputStream getInputStream() throws IOException {

		if (!connected)
			connect();

		if (resource == null) {
			throw new FileNotFoundException(
					getURL() == null ? "null" : getURL().toString());
		}

		// Reopen resource
		try {
			resource = (Resource) context.lookup(path);
		} catch (NamingException e) {
			// Ignore
		}

		return (resource.streamContent());
	}

	/**
	 * Get the Permission for this URL
	 */
	@Override
	public Permission getPermission() {

		return permission;
	}


	// --------------------------------------------------------- Public Methods

	/**
	 * List children of this collection. The names given are relative to this
	 * URI's path. The full uri of the children is then : path + "/" + name.
	 */
	public Enumeration<String> list()
			throws IOException {

		if (!connected) {
			connect();
		}

		if ((resource == null) && (collection == null)) {
			throw new FileNotFoundException(
					getURL() == null ? "null" : getURL().toString());
		}

		Vector<String> result = new Vector<String>();

		if (collection != null) {
			try {
				NamingEnumeration<NameClassPair> enumeration =
						collection.list("/");
				UEncoder urlEncoder = new UEncoder(UEncoder.SafeCharsSet.WITH_SLASH);
				while (enumeration.hasMoreElements()) {
					NameClassPair ncp = enumeration.nextElement();
					String s = ncp.getName();
					result.addElement(
							urlEncoder.encodeURL(s, 0, s.length()).toString());
				}
			} catch (NamingException e) {
				// Unexpected exception
				throw new FileNotFoundException(
						getURL() == null ? "null" : getURL().toString());
			}
		}

		return result.elements();

	}


}
